Tire-frotectiitg sigetal



J. E. KENNEDY ET AL TIREBRoTEcTING SIGNAL Filed Aug. 17, 1925 latented @et E, i928.

TOEN IE. KENNEDY AND MICHAEL A. KENNEDY, 0F LOS ANGELES, CALFORNIA.

TIRE-PROTECTING SIGNAL.

Application led .August 17, 1925. SeralNo. 50,51'

This invention relates to protect-ion ot' pneumatic tires against over inflation or under inflation, either of which is highly objectionable and especially so in the case of so called balloon tires Whose characteristic features are low air pressure and thin flexible walls.

The use of the ordinary tire pressure gauges that areapplied successively to each tire require the removal and replacement ot each dust cap and the careful reading of a more or less finely graduated scale when it is applied to each tire, hence the motorist Will seldom trouble to test his tires with such a gauge except possibly as he occasionally inflates a tire7 which he sees has gone nearly flat.

rlfloe present invention is intent/ed to provide a. permanent-ly attached signal, of such marked visibility that a mere glance at the tire from a moderate distance vxill Warn him that any over-inflated or under-inflated is in such condition as to need attention.

Since in the case of balloon tires a relatively smallchange from the standard normal air pressure for a given tire may be seriously detrimental to the tire if used Without correction, and such a small change is attended With but a small movement orn an airresisting plunger, We have devised a special tire signal device that is accurately sensitive to small change in air pressure and at the same time is combined with a multiplying indicator having a sutlicient range of movement to give markedly conspicuous indication of even a small degree of over-inflation or of under-inflation, as the case may be. o1. arrangement being such that it is not adversely affected lov road shocks or vibration and free f oi aberrations or derangements caused by exposure to the dirt. dustyivater encountered When traveling on the road.I u consideration ot great practical importance, in this class ofL devices.

Broadly speaking the invention comprises a yieldingly movable air-resisting and air'- actuated plunger mounted in a casing adapted to be permanently attached to the stem of a pneumatic tirea and operatively connected with an oscillatory indicator of sufiicient radial length to move through an arc of substantiall;7 l 'eater length than the .flistance its acti ting plunger travels to its diliiterenl 'nos' ons of balancee Which are indif cated the ,umNA y lag indicator..

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fr feature of practical importance is that this multipljgging indication is accomplished Witl it danger ot air leakage through the dei'. While avoiding the frictional resistance Lue to a tight fitting piston or the inaccuracies involved in the use of a distensible tube of elastic rubber or other material which isrsubject to deterioration when kept under stress.

These and other features of the invention will be. described in the following specification and will be defined in the claims hereto annexed.

ln the accompanying drawings I have illustrated a simple7 convenient and reliable construction and arrangement embodying the principles of this invention, in which:

Figure l is a vertical central section of the device ready for application to a pneumatic tire.

Figure 2 is a cross section taken at right a l to the plane of Figure l, the coupling me nber being omitted.

Figure 3 isV a view.l similar to Figure l, shoivinj the position of" parts When the tire under-inflated.

Figure llis a detail of the flexible air-sealdiaphragm. A Figure 5 is a front elevation of the device.

Figure o isa front elevation of a protective cap or cover adapted to be applied thereto.

l" jure 7 is a detail i n central section showing amodilication of the diaphragm guide.

In the practice of this invention. according to the form illustrated, We employ a hollow body 20. providing a compressed air chamber. which is adapted to be permanently but detachably coupledl to the stem of a pneumatic tire. communication 'for the admission of air being provided by the air passage through the internal boss which projects far enough inside the tire nipple to unseat the tiro valve. f

A lateral nipple 2,1 controlled by any usual form of check valve 24. serves to permit the inflation of the tire Without removing the signal device from the tire stem.

An indicator casing 30 is secured to the internally threaded flange Qa of the body member il()7 by means of a spanner ring nut l which overlaps a shoulder or flange 30', and through interposed Washer 27 'firml' clamps the peripheral portion of a disk-like flerible diaphragm 2G tightly annular armed the had?? vtween the spindle 34 and the sleeve 33.

This diaphragm 2G is preferably made of slightly larger diameter than the interior seatso that when the diaphragm 26 is secured in place, it assumes a bowed or cup form, as indicated in the lower dotted lines ot Figure l. This allows the diaphragm to move from bowed position on one side ot the central plane to bowed position on the otherside without depending' upon the stretch of the diaphragm, so that there is no deterioration due to its being' maintained under tension, and the elasticity or stretch ot the diaphragm is not a factor affecting the correct indication of p yassure.

For the pressure-indieating scale we provide a hollow plunger or sleeve 33 adapted to slide inside the longitudinal bore ot the ci sing 30, but not with a smile; enough tit to attord appreciable itrictional resistance, and in the bottom or lower end. as the device is illustrated in the drawing, is inserted a tension adjusting spanner nut 35, which has peripheral engagement with the internal threads in the lower end of the sleeve 33 and has internal threaded engagement with the reduced threaded lower end 34 ot a plunger '84, both internal and external threads olf the nut being', of the same pitch so that the rel as tive positions ot the interior plunger or spindle 34 with the plunger sleeve 3S. is not affected when the nut is screwed up or down to vary the tension of the helical. spring 36, which is inserted in the annular space be- This helical spring is of predetermined strength and is disposed so that its upper end thrusts against a transverse ledge ot the casing 30, which ledge centrally perforated to aitford a guiding bearing ter the upper end ot the plunger or spindle 341e. The downward thrust of the spring against the nut presses the lower end ot the Vplunger against the diaphragin 2G to yieldingly oppose and counterbalance the air pressure on the under side ot said diaphragm.

As this'device is not intended for a pressure gauge that will show considerable variations in pressure. and is intended to indicate .small variations in pressure with a high degree et visibility te render such change indi- `cations easily discernable from a distance, we have provided what may be termed a multiplying signaling or indicating means allerding a relatn ly large range ot movement ot the indicat 1' 'in correlation with slight changes ot pos tion ot the actuating plunger.

To this end the upper end. of the plunger is slotted to receive a thin disk-like wing 3S@ ot a rotative arbor 38, said wingI being notched peripherally to receive a transverse pin 37 secured in the upper end of the plunger. The reduced front end Zl() of this arbor carries a point-er a ot' such length that the moveg ment oi' the end et the pointer7 with relation to conspicuous display signal. devices, will extend through a substantially greater range or arc oi movement than the actual axial movement of the plunger itself.

The indicator casing is provided with a liront plate or cover 50, preferably provided with a peripheral raised edge or protective ledge extending out beyond the tace ot the pointer so that the pointer may be left eX- posed to vi ew, while guarded against any erlternal sid`e-swiping- In correlation with the pivoted pointer 40, we employ `alipropriate display signals markedly contrasting in appearance both with the pointer and with the exposed surface ot the cover 50, which forms the background 'lor the pointer. Preferably these conspicu-' ous display signals are in the form of an intcrrupted rib having a gap at is middle portion over which the end ot 'the pointer will stand when the tire pressure is at the normal standard tor a given tire carrying a given load.. ln Figures l and 2 the diaphragm and plunger stand approximately in the position which is appropriate to indicate, correct nor- 0.al pressure for the tire. In Figure 3 the diaphragm and thel plunger are shown in a position of partial defiation which would re sult in moving the pointer to the right hand 4display portion ol the signal-indicating plate which is marked with the minus or other symbol indicative of under-inflation.V An excessive pressure will similarly be noted. by the snf'ing of the pointer to the lett hand display s` ial marked with the plus or other timepressure indication.

To protect the diaphragm from being cut by the lower edge ot the sleeve member ot the plunger, wepreferably employ a covering` disk Q8 which is interposed between the diaphragm and the lower end ot' the sleeve.

It will be seen that this device is practically adapted for pern'ianent attachment to the tire since it will not be adversely alfected by the vibration and roadv shock to which it is subjected, yet it is sensitive to slight changes in pressure of which it gives a multiplied or magnified indication readable at a distance. It is not affected by any appreciable trictional resistance which will change with wear, ner

.it dependent upon the elasticity or stretch oli' rubber, the co-eflicient oi which changes when rubber is kept constantly in a stretched condition. The construction is such that its ae tion is not impaired by accunnilation ol dust, and it may still further be protected by means oit a cover or cap which can be forced on over the indicator casing with its lower end opposite the pointer and signaling indicia entirely opened er closed by a transparent panel. As the indicating signal is secured to the body by a connection permitting rotative adjustment, the tace of the indicator may be always set to face outwardly when applied to the wheel, and yet secure a perfectly tight seating of the air-sealing diap i ragni.

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lessees ing ust large enough to allow the sl al, and its cap 28 to pa, ci ectually in that case, servaig to he slacl; ot the 4diaphragin Yfrom hugging the lower en ot the sleeve its cap.

TWhat we claim t l. A visual safety signal for a pneumati tire embracing an air-tight casing having' laterally valved air inlet adapted to be cured to a tire stem by permanent airtight coupling, a pistou casing red to the outer end ofthe said air casing, an i mpertorat confining diaphragm of pliable airtight ric secured across the open end et the tight casing to confine the airi theres, said diaphragm having suilicient tullness, when secured in place, to allow it to bul on either side of a medial plane withou stretchii extensible piston member comprising aud outer elements adjustably sec gether, a helical compression spriiv V acting to thrust the inner end ot in counter-balancing resistance phragm, means for guarding the ot said piston against gripping around its periphery on the part or the diaphragm when the latter is bulged routwardly by air pre, sure, and an exterior pointer ass ciated with two widely spaced oistantlv visible signal members indicative, respeetivf ly. et over-initiation and under-inflation o t the tire, said pointer being actuated to more between said signal members according Vto the pressure counter-balancing position ot said piston.

2. A visual s tety si 9nal 'for pneumatic tires einbracing` in combination a hollow casing adapted to be pern aneutly secured to tire stem maintain constant communication with the tire and having' a lateral lved airsupply port, a piston casing adapted to be secured to the open end of said hollow cas (f an imperiiorate diaphragm ot sott pliabi terial having its peripheral portion pinched between the two casings when are secured together end to end to prevent passage ot air i'ironione to the other., a springpressed piston slidably mounted in the piston casing and resting loosely against said irnoertorate diaphragm to oppose a counterbalancing resistance to varying degrees ot air pressure against the opposite side of said diaphragm, and an external pointer correlated with two contrasting signal bands of high visibility to render them conspicuous at a distance, said pointer being operatively connected with the piston to be moved to and fro as the tire pressure rises or falls to give indication, visible at a distance, ot trie over-intlation or undenintlation oit the tire.

3. ln a device of the class described, the combination ot an air-tight casing adapted to be Secured to a tire stein and maintain constant communication with the` tire,` an impertorate air-coniining diaphragm of pliable material secured across the open end oit said casing to confine the air therein, a piston casing secured on the opposite side ot said diaphragm, and a s ning-pressed piston arranged to oppose counter-balancing pressure against the' outer tace olE said diaphragm, said piston comprising inner and outer co-axial members adjustably secured one to the other, one resting upon the diaphragm and the other having operative connection with an indicating pointer, said pointer being mounted exteriorly of the piston casing.

1l. ln a device of the class described, the combination ot two casing members .secured end to end, an imperiiorate air-confining diaphrac'in interposed between said two casings, a spring-pressed piston resting against the outer face of said diaphragm and comprising Vinner and outer members adjustably oonnected together by an interposed spring-supporting and tensioning nut arranged to var v the tension or the spring without varying the relative position ot the two casing members, and a pointer operatively connected with one ot said piston members to visually indicate in relation to signals visible at a distance variations in tire pressure.

5. ln a device ot the class described, the combination with a.` valve air-pressure chamber adapted to contain constant communica tion with the tire stem., a piston chamber secured thereto, an iniperitore-.te diaphragm preventing the passage of air 'from one casing to the other, an indicating pointer mounted ou the piston casing to indicate at a distace from the tire over-inliatiou or under-inflation ot the tire, and a piston resting upon said diaphragm, said piston comprising eXtensibly adj; ustable members connected by a tensioning nut so as to vary either the effective length the piston or the tension ol' the springl without one adjustment allecting the other, substantially as described.

ln witness whereof, we have subscribed the above specification.

` JOHN E. KENNEDY.

M. A. KENNEDY. 

